SExtractor Draft - METU Astrophysics
SExtractor Draft - METU Astrophysics SExtractor Draft - METU Astrophysics
10INTERP TYPE ALL keywords (n ≤ 2) Interpolation method from thevariance-map(s) (or weight-map(s)):NONE– no interpolation,VAR ONLY – interpolate only the variance-map(detection threshold),ALL– interpolate both the variance-mapand the image itself.MAG GAMMA float γ of the emulsion (takes effect inPHOTO mode only).MAG ZEROPOINT float Zero-point offset to be applied to magnitudes.MASK TYPE CORRECT keyword Method of “masking” of neighboursfor photometry:NONE– no masking,BLANK– put detected pixels belonging toCORRECTneighbours to zero,– replace by values of pixels symetricwith respect to the source center.MEMORY BUFSIZE — integer Number of scan-lines in the imagebuffer.Multiply by 4 the frame widthto get equivalent memory space inbytes.MEMORY OBJSTACK — integer Maximum number of objects that theobject-stack can contain. Multiply by300 to get equivalent memory space inbytes.MEMORY PIXSTACK — integer Maximum number of pixels that thepixel-stack can contain. Multiply by16 to 32 to get equivalent memory s-pace in bytes.PARAMETERS NAME — string The name of the file containing the listof parameters that will be computedand put in the catalogue for each object.PHOT APERTURES — floats (n ≤ 32) Aperture diameters in pixels (used byMAG APER).PHOT AUTOPARAMS — floats (n = 2) MAG AUTO controls: scaling parameterk of the 1st order moment, and minimumR min (in units of A and B).PHOT AUTOAPERS 0.0,0.0 floats (n = 2) MAG AUTO minimum (circular) aperturediameters: estimation disk, andmeasurement disk.PHOT FLUXFRAC 0.5 floats (n ≤ 32) Fraction of FLUX AUTO defining eachelement of the FLUX RADIUS vector.PIXEL SCALE — float Pixel size in arcsec (for surfacebrightness parameters, FWHM and s-tar/galaxy separation only).SATUR LEVEL — float Pixel value above which it is consideredsaturated.SEEING FWHM — float FWHM of stellar images in arcsec (onlyfor star/galaxy separation).
11FULLSTARNNW NAME — string Name of the file containing the neuralnetworkweights for star/galaxy separation.THRESH TYPE RELATIVE keywords (n ≤ 2) Meaning of the DETECT THRESH andANALYSIS THRESH parameters :RELATIVE – scaling factor to the backgroundRMS,ABSOLUTE – absolute level (in ADUs or in surfacebrightness).VERBOSE TYPE NORMAL keyword How much SExtractor comments itsoperations:QUIET– run silently,NORMAL– display warnings and limited infoconcerning the work in progress,EXTRA WARNINGS – like NORMAL, plus a few more warningsif necessary,– display a more complete informationand the principal parameters of all theobjects extracted.WEIGHT GAIN Y boolean If true, weight maps are considered asgain maps.WEIGHT IMAGE weight.fits strings (n ≤ 2) File name of the detection and measurement“weight-image”, respectively.WEIGHT TYPE NONE keywords (n ≤ 2) Weighting scheme (for single image, ordetection and measurement images):NONEBACKGROUNDMAP RMSMAP VARMAP WEIGHT– no weighting,– variance-map derived from the imageitself,– variance-map derived from an externalRMS-map,– external variance-map,– variance-map derived from an externalweight-map,3.3 The catalog parameter fileIn addition to the configuration file detailed above, SExtractor needs a file containing the list ofparameters that will be listed in the output catalog for every detection. This allows the softwareto compute only catalog parameters that are needed. The name of this catalog-parameter fileis traditionally suffixed with .param, and must be specified using the PARAMETERS NAME configparameter.3.3.1 FormatThe format of the catalog parameter list is ASCII, and there must be only one keyword perline. Presently two kinds of keywords are recognized by SExtractor: scalars and vectors. S-calars, like X IMAGE, yield single numbers in the output catalog. Vectors, like MAG APER(4) or1 Optional parameter
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11FULLSTARNNW NAME — string Name of the file containing the neuralnetworkweights for star/galaxy separation.THRESH TYPE RELATIVE keywords (n ≤ 2) Meaning of the DETECT THRESH andANALYSIS THRESH parameters :RELATIVE – scaling factor to the backgroundRMS,ABSOLUTE – absolute level (in ADUs or in surfacebrightness).VERBOSE TYPE NORMAL keyword How much <strong>SExtractor</strong> comments itsoperations:QUIET– run silently,NORMAL– display warnings and limited infoconcerning the work in progress,EXTRA WARNINGS – like NORMAL, plus a few more warningsif necessary,– display a more complete informationand the principal parameters of all theobjects extracted.WEIGHT GAIN Y boolean If true, weight maps are considered asgain maps.WEIGHT IMAGE weight.fits strings (n ≤ 2) File name of the detection and measurement“weight-image”, respectively.WEIGHT TYPE NONE keywords (n ≤ 2) Weighting scheme (for single image, ordetection and measurement images):NONEBACKGROUNDMAP RMSMAP VARMAP WEIGHT– no weighting,– variance-map derived from the imageitself,– variance-map derived from an externalRMS-map,– external variance-map,– variance-map derived from an externalweight-map,3.3 The catalog parameter fileIn addition to the configuration file detailed above, <strong>SExtractor</strong> needs a file containing the list ofparameters that will be listed in the output catalog for every detection. This allows the softwareto compute only catalog parameters that are needed. The name of this catalog-parameter fileis traditionally suffixed with .param, and must be specified using the PARAMETERS NAME configparameter.3.3.1 FormatThe format of the catalog parameter list is ASCII, and there must be only one keyword perline. Presently two kinds of keywords are recognized by <strong>SExtractor</strong>: scalars and vectors. S-calars, like X IMAGE, yield single numbers in the output catalog. Vectors, like MAG APER(4) or1 Optional parameter
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